1

MU524 Vari-Mu Tube Compressor / Re: VARI-mu build

« on: February 19, 2023, 03:28:37 AM »

after 10 secs??? then no its hanging around 2.4 vdc

2

MU524 Vari-Mu Tube Compressor / Re: VARI-mu build

« on: February 19, 2023, 03:14:17 AM »

the voltage stayed around 2v.... maybe I was too anxious... ill look again...

3

MU524 Vari-Mu Tube Compressor / VARI-mu build

« on: February 17, 2023, 06:28:41 AM »

Having issues with build  - 

Going on step 5-6 - tube isnt really warming up - (not as warm as ive felt others) 
Sound is passing - Oddly When input pot is turned up - the volume goes down.
The meter lights up just fine. Output pot does give gain. haven't had a chance to test the recovery. 
I've done readings on all test points 

The reading goes as follows:


V+ 15.69
V- -15.74

TP1 - 40.59
TP2 - 40.05
TP3 - 0
TP4 - 0 
TP5 - 0
TP6 - 0

PLEASE ADVISE..

Thanks keenan 

4

CP4500 Stereo Bus Compressor / Re: Unable to level match on Channel 2, voltage issues on channel 1

« on: May 22, 2022, 09:16:14 PM »

Same issue here 

5

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 18, 2022, 04:01:09 PM »

6

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 17, 2022, 04:32:49 PM »

Well I've tried several. And still can't get a match. It's off by 1.7db

7

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 16, 2022, 12:13:15 PM »

Moving and changing the 1646 from ch a to b 

8

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 14, 2022, 10:24:43 AM »

Same. I noticed that when I changed out the chips that the volume changes channels. The 1646 chips are new from 
Mouser.

9

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 13, 2022, 05:56:09 PM »

Ok changed. What should I be looking for

10

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 12, 2022, 05:14:20 PM »

Check the resistor value (with power off, U16 removed, Trimmer T2 fully CW) between TP7 and U16 pin 6 : 5k7 ? = 5.682k ohm

Check the resistor value (with power off, U16 removed, Trimmer T2 fully CCW) between TP7 and U16 pin 6 : 4k7 ? 4.699 k ohm

11

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 12, 2022, 05:07:03 PM »

tp7 with u17 removed comes to 1.694 vac

12

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 12, 2022, 04:44:45 PM »

Will do stand by

13

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 11, 2022, 01:57:05 PM »

Yes

14

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 09, 2022, 05:29:50 PM »

With make up @+20 I get -2.384vdc with second channel attached

-2.37vdc without board 2 attached 

15

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 09, 2022, 12:32:22 PM »

Yes. 0v with channel 2 installed and without... fluctuating no more than .5 -/+vac moving make up 0 to +15

16

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 07, 2022, 12:25:42 AM »

step 1 voltages

v+ 15.2
v- 16.2
-12v 11.5
+12v 11.7

step 2

tp 1,2,3,4,11,12 =0VDC

step 3

tp12 = -2.9vdc

step 4

tp13 @-1.8vdc
      @2.9vdc

step 5 

tp4 @-15TH =0.21
    @+15TH =.058
TP5 @+15TH =.334VDC
      @-15TH =-2.221VDC
TP11@+15TH =.012
      @-15TH=-3.39
TP12@-15TH=3.4VDC
        @+15TH=0

STEP 6
TP1=1.5VAC
TP2=1.439VAC
TP3=1.51VAC
TP4=0.06VAC
DCV = -0.001

STEP 7
TP1=1.5VAC
TP2=0.470VAC
TP3=1.51VAC
TP4=0.217VAC
TP11=-3.39VDC
TP12=1.03VDC
TP13=1.59VDC

CHANNEL 2

-V = 16.21
+V = 14.77
-12V= 11.87VDC
+12 = 12.03

STEP 2 C2

TP6=0
TP7=0
TP8=0
TP9=0

STEP3 C2

TP6=1.5VAC
TP7=1.36VAC
TP8=1.5
TP9=0.06

STEP4 C2
TP6=1.5VAC
TP7=0.4VAC
TP8=1.5VAC
TP9= 0.2VAC

VDC U16 =.058

17

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 04, 2022, 05:30:36 PM »

Yes at 0 make up those are the values 

18

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 02, 2022, 08:48:58 PM »

TP7 at 0 makeup is 1.3vac and @+20 makeup is at 13.12vac

19

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 02, 2022, 08:45:36 PM »

TP7 value seems to be extremely high compared to what im supposed to be getting ---------12.15VAC where as its supposed to be 1.5vac

20

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 02, 2022, 08:01:49 PM »

All voltage checks are fine at this point. Channel 2 is .5 - 1.5 db off. I've moved the trims and nothing changes.

21

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 02, 2022, 05:56:17 PM »

I can't get the levels on the channels to balance... the meter does jump. 

22

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 02, 2022, 05:43:12 PM »

English?? Plz

23

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 02, 2022, 05:13:44 PM »

Correction -1.8vdc to 2.8vdc

24

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: May 02, 2022, 05:12:14 PM »

Tp13 does change with threshold is turn... from 1.8vdc to 2.8vdc

25

CP4500 Stereo Bus Compressor / Re: Output Issues On CP4500

« on: April 30, 2022, 05:15:10 PM »

Checked the of the resistors. all seem to be what is required. Swapped the OPA chip and got the same result and numbers. Please advise....